A thought on Hurricane strength in the Gulf

Some time before Hurricane season we posted a reference from the UK where one of their submarines had been measuring Arctic ice. It found that one of the driving forces for the Gulf Stream, the Odden ice shelf, which used to grow out into the Greenland Sea from the Arctic ice cap each winter, had stopped forming.  As a result it no longer melted in the spring driving cold water down to the bottom of the Atlantic, and thereby helping power the Gulf Stream.  In consequence with the GS running slower less heat is being taken out of the Gulf and sent North.  

While I do not have the original reference to hand, the Times has an equivalent story, that describes what has occurred.  

With more heat left in the waters of the Gulf, this provides additional power to hurricanes that enter that body of water, with consequences that we have seen in Katrina, and, sadly, may now begin to expect from Rita.  It also means that the winters in Western Europe may not be as pleasant in the future.  Which given some of the depletion rates from the supplies in the North Sea, and the inability of Russia to significantly increase exports, may be giving the British Government, among others, a bit of heartburn right now.

Update [2005-9-19 1:19:45 by Prof. Goose]:And, under the fold is a link to the latest modeling of Rita. No clue yet, folks.

Update[2005-9-19 8:50 by Heading Out]: There is also the reference to the National Geographic picture of the platform locations in the Gulf.

Scientists have worried about this possibility for years.  I had heard them discuss the possibility of much colder weather in northern Europe, but I don't recall anyone speaking of a much warmer gulf and all that implies.

And yet we still have nutjobs who deny that global warming even exists.  And I can just see it now - they will claim that global warming must be wrong because the weather got colder, not warmer.

People are always thinking short term. Imagine the traders that sold off energy the Friday before Katrina hit...

Meanwhile... virtually negligible changes from Friday's MMS report:


Today's shut-in oil production is 837,648 BOPD. This shut-in oil production is equivalent to 55.84% of the daily oil production in the GOM, which is currently approximately 1.5 million BOPD. Approximately 35% of shut in oil is as a result of onshore infrastructure problems.

Today's shut-in gas production is 3.375 BCFPD. This shut-in gas production is equivalent to 33.75% of the daily gas production in the GOM, which is currently approximately 10 BCFPD.

The cumulative shut-in oil production for the period 8/26/05-9/19/05 is 24,735,216 bbls, which is equivalent to 4.518 % of the yearly production of oil in the GOM (approximately 547.5 million barrels).

The cumulative shut-in gas production 8/26/05-9/19/05 is 115.919 BCF, which is equivalent to 3.176% of the yearly production of gas in the GOM (approximately 3.65 TCF).

Before we get too carried away blaming Global Warming (disclaimer:  I do NOT doubt the existence of human-induced Global Warming), the National Hurricane Center believes that Global Warming is playing a neglible role in the hurricane season:

This confluence of optimal ocean and atmosphere conditions has been known to produce increased tropical storm activity in multi-decadal (approximately 20-30 year) cycles. Because of this, NOAA expects a continuation of above-normal seasons for another decade or perhaps longer. NOAA's research shows that this reoccurring cycle is the dominant climate factor that controls Atlantic hurricane activity. Any potentially weak signal associated with longer-term climate change appears to be a minor factor.

While global warming is unlikely to produce more huricanes, it may be responsible for more intense huricanes.
No, no.  I think you misunderstand my point:

I'm not saying that global warming won't cause more severe hurricanes.  I'm not even saying that it won't cause more hurricanes of whatever strength (though, like you said, it may not).

I'm just saying that the climatologists don't believe the current hurricane season's severity may be attributed to Global Warming.

In other words, global warming may severely impact our environment (it already is doing so, I believe), but this hurricane season is not the proof many people think it might be.  This season's severity is well-understood in light of the normal multi-decadal activity cycle.  Any influence from global warming is minor by comparison -- minor enough that we can't extract it from the pronounced impact of the multi-decadal cycle.

gunnk wrote:
"This season's severity is well-understood in light of the normal multi-decadal activity cycle.  Any influence from global warming is minor by comparison -- minor enough that we can't extract it from the pronounced impact of the multi-decadal cycle."

I made a link to Real climate where they discuss the relation between Global Warming and Hurricanes. They discuss mostly the Emanuel (2005) article from Nature. You can go to figure 2 at http://www.realclimate.org/index.php?p=181#comments

When you look at the figure 2 that it is a measure of total power dissipated annually by tropical cyclones in the North Atlantic (the power dissipation index "PDI") compared to September tropical North Atlantic SST (from Emanuel, 2005) you can note some interesting things:
1- there is a multi-decadal cycle;
2- there is a surge at hurricane activity that go ABOVE the multi-decadal cycle AFTER 1995.

Any statistical test will show that the hurricane activity after 1995 is ABOVE the normal and cannot be expected from the multi-decadal cycle. If you don't belive me, just believe at your EYES. LOOK THE FIGURE 2.

If you look the figure 2 it is EVIDENT that this season hurricane's activity CANNOT be explained by multi-decadal acrivity cycle and that any influence from Grobal Warming ISN'T a MINOR influence. But don't belive me, just go look the figure 2 http://www.realclimate.org/index.php?p=181#comments and come to your own conclusions. Just learn to think.

The REAL data is there. And IMHO the real data contradict gunnk opinion that "this season's severity is well-understood in light of the normal multi-decadal activity cycle" and that the Global Warning influence is "minor".

João Carlos

sorry my bad language, my native language is portuguese.

I still believe you have to look at more data over a greater time frame to determine the degree to which change is occurring.  Look at the data on historical hurricane strikes on the United States for example:


From this historical data there is no sign of a trend.  I know that the data set is NOT complete for all storms (only those that hit the U.S.), but it gives a good sample as a quick check for historical trends.

For the moment, I will continue to stand by the NWS statement that the effect of the normal hurricane cycles currently outweigh the effect of global warming on the current season.

Again, this is NOT an attempt to disparage the reality of global warming.  I'm just saying that we should not readily attribute the current season's ferocity to global warming if other, known causes provide a satisfactory explanation.

There is ample evidence of global warming elsewhere in the climatological data.  We don't need to try to point to dramatic examples which may prove unfounded.  To do so undermines attempts to educate the public and policy-makers as to the reality of the problem.  It moves the debate from science to advocacy.

I'm afraid you and I'll will have to respectfully disagree.  Contrary to your comments, I do know how to think.  I hold a degree in physics and worked for several years as a member of the Indoor Air Pollution research team at the U.S. EPA.  I just don't see the same pattern that you do -- at least not one that seems to hold up over longer time periods.  Therefore, in absence of the trend which you perceive, we reach different conclusions.

I'm not saying that global warming won't cause more severe hurricanes.  I'm not even saying that it won't cause more hurricanes of whatever strength (though, like you said, it may not).

I'm just saying that the climatologists don't believe the current hurricane season's severity may be attributed to Global Warming.

I think that you misspoke because those two paragraphs are conflicting.  Perhaps you meant, "I'm just saying that the climatologists don't believe the current hurricane season's frequency may be attributed to global warming.  In my pointy little head I equate hurricane severity with intensity.
No conflict.  I'm not speaking of the severity of the hurricanes, but of the severity of the season.

The severity of the season is a composite of the frequency and intensity of the individual storms.

There are a discussion at Real Climate site about the relation between Global Warming and Hurricanes. They analyse the last data and it is interesting read ALL the comments there.


Currently the climatologists have no diveregence about the fact there is Global Warming and that it is caused by humans. The only discussion they have now is how much hot the climate will go, but there is no more discussion if there are Gobal Warming.

But the USA government prefer say that there are no scientific evidence about the Global Warming, while Bush want Inteligent Design (aka CREATIONISM) be tauch at your public schools.

Sadly, it is better be preparated to live at not pleasant weather. You know, strong Hurricanes every year, cold weather at Europe, dryness at North America.

João Carlos

Sorry the bad english, my native language is protuguese.

When I taught the greenhouse effect and global warming concepts to my undergrad classes almost 20 years ago I stressed that few models would accurately predict effects on a local area.

I also stressed that most models predicted greater swings in ALL weather events.  Higher highs, lowere lows, drier droughts, wetter wet cycles, more high wind events, more days with no wind.  And there could be more extremes at a single location in a single year.  On AVERAGE this would result in a slightly warmer biosphere global wide over any 12 month period.  

This is lethal to many plant species, which was my focus.  Plants can't move out of the way of weather extremes.  They either adapt or dieoff.  Rapid changes don't allow enough time for adaptation of species or replacement with new species.  The result is loss of vegetaion.  Which also tends to reinforce extremes in weather over time, think deserts.  

Global warming tends to reinforce natural swings, but not overwhelm them which is why it has been difficult to prove global warming exists.  It is all background on top of greater natural variation.  I think of it as larger standard deviations around the means.

So will you ever be able to say that global warming contributed to a greater hurricane season or individual storm?  I doubt it, but statistics will say there is a greater probability that more very large storms will occur if the overall heat load of the planet is increased affecting all the triggers for hurricanes.  We are forewarned with this knowledge and should use it for planning, not ignore it or say it doesn't exist.

It is relatively more salty water that forms in the north Atlantic by evaporation that drives the descending branch of the thermo-haline circulation.  Large influxes of fresh water from glacier melt disrupt the formation of salty water in the upper layers of the north Atlantic and stop the descent.  This is the mechanism believed to account for the climate change during the Younger Dryas period about 11 thousand years ago.

In the case of the Odden ice shelf, it is its formation that is important and not its melting.  When it forms it expels slatier water that initiates the formation of sinking water columns.  A good article on this issue is:  http://www.timesonline.co.uk/article/0,,2087-1602579,00.html

I am not getting a warm and fuzzy feeling about Rita. Look at this NHC Data and look especially at the Strike Probability and the 3 Day Cone.

In the climate and weather community, it seems that the people who specialize in hurricanes (William Gray at Colorado State University, Chris Landsea of NOAA/NHC and others) tend to downplay any connection between recent large intense storms and climate change. For example, Landsea became incensed earlier this year when climate scientist Kevin Trenberth of NCAR suggested a connection -- and he resigned from the IPCC committee studying the problem. The Real Climate discussion (from climate scientists) linked in by previous posters here disputes what the hurricane specialists say. Those in the MSM are able to draw any conclusion they want because there is an ongoing scientific debate about the problem and they themselves know nothing.

HO's post here seems to concern the Thermohaline Circulation (THC), as discussed by malkontent. The Times article cited was a lead-in to another thread on Real Climate Gulf Stream Slowdown?. Look particularly at comment #26 there for a brief discussion of the (lack of) a connection between the THC and hurricanes.

It makes perfect sense to me that warmer Gulf waters would lead to an increase in the intensity, if not the frequency, of hurricanes in the Gulf.  Claims to the contrary by a US government agency, such as the National Hurricane Center, have to be considered in the context of a government that fires anyone who contradicts its ideological views (e.g. that climate change is not the result of human activity).  Even "independent" scientists are under pressure to downplay human impacts on climate, because most rely on government grants, and the government has been harrassing scientists who take inconvenient views.

The article mentions that a shutdown of the Gulf Stream would mean that "the winters in Western Europe may not be as pleasant in the future."  Actually, it was my understanding that a shutdown in the Gulf Stream would lead not just to colder winters but to longer winters, similar to those at comparable latitudes elsewhere.  For example, London is about at the same latitude as St. Anthony at the northern tip of Newfoundland.  Without the Gulf Stream, London could have a climate similar to St. Anthony.

London's current average temperature in January is 6° C.  St. Anthony's average for January is -11°C.  The average daily minimum in London is not now below 0° C for any month of the year.  The average daily minimum in St. Anthony is below 0° C from November through May.  London now has more than 5 months of frost-free weather per year, and hard frosts only occur during 3-4 months.  St. Anthony has no more than 3 months of frost-free weather, with hard frosts for 6 months.

The implications of this for the growing season in Britain and other parts of Europe north of the Alps are alarming.  It might become impossible to grow wheat north of Lyon or so.  The need for heating fuel could crash right up against peak oil, with people dying or exposure or immune systems weakened from coping with extreme cold.

I grew up in Minneapolis, and if you look at a globe, you will see that it lies roughly at the same line of attitude as Venice.  I used to joke with people that Minneapolis isn't that cold - it has a Mediterranean climate.

This wasn't quite what I had in mind though.

As of Friday's EIA special reports on Katrina, these interesting comparison charts:



And, a confirmation of what us amateurs have been suggesting:

While the peak crude oil production loss from Hurricane Katrina was similar to Hurricane Ivan last year and even less than Hurricane Dennis earlier this year, the pace of restoration is expected to be much more similar to Hurricane Ivan than any of the other recent hurricanes. For example, while the peak daily loss in crude oil production during Hurricane Dennis was slightly more than suffered following Hurricane Katrina, within a week of the peak loss, crude oil production following Hurricane Dennis was back to normal while it will likely be months before crude oil production is back to normal following Hurricane Katrina.
Just looking at a map would explain the high temperature of the GOM. Most of its water never leaves but just circulates over and over in the same basin between Texas and Florida.  With winter temps not being as low as 20-30 years ago the summer heating just carries over to the following spring.
As for any connection to the Greenland Sea I think some of you confused the Gulf Stream with the Gulf of Mexico. The two are on opposite sides of Florida.
Actually, the Gulf Stream does flow out of the Gulf of Mexico. It flows through the Straits of Florida north of Cuba.  So slower sinking of surface water off of Greenland could slow the exit of surface water from the Gulf of Mexico, thereby allowing its heat to increase.
Interesting discussion all around and I especially appreciate NC's nuanced views regarding "larger standard deviations around the means."  To some extent the recent concerns over hurricanes has a lot to do with the fact that from around 1970 to 1995 the value and scale of property in the storm prone areas has increased dramatically, including both urban development and GOM oil/gas operations.

All this took place while we were in the midst of the less active phase of the multi-decadal oscillation which may have given some people a false sense of what is "normal."  And unfortunately, modern humans are only now finally starting to realize that "normal" is a moving target that depends on the scale of observation.

For those interested in climate change, here are links to the three separate parts and the author Q&A for a series about climate change that ran in the New Yorker in April/May 2005.  It is a very long series, but in my opinion, one of the best MSM summaries of the recent science that I have read.

Climate of Man (Part 1)

Climate of Man (Part 2)

Climate of Man (Part 3)

Q&A with "Climate of Man" Author, Elizabeth Kolbert

For those interested in other aspects of sustainable development and how humans might view/address issues such as climate change, natural resource depletion and the like in the years to come, I highly recommend the Resilience Alliance position paper from the 2002 World Summit on Sustainable Development held in South Africa:


You can also learn more about the key concepts espoused by the Resilience Alliance at:


Collective adversity mandates collaborative adaptation...